When you are faced with a rounded-off, rusted-tight or painted-over bolt, bolt extractors will break it free. This listing is for the 10504634 base set and the 10504635 expansion set to cover the full range of sizes. Features Reverse spiral flutes are designed to bite down and provide maximum gripping power. Tougher than tool steel high carbon steel ensures longer life and greater durability. 3/8 square drive for use with hand ratchets, impact wrenches and air ratchets. The hexagonal section can be used with a flat wrench, pliers, adjustable wrench etc. Made in USA by Irwin Tools, so quality is assured, comes with a full guarantee from Irwin Tools.